16 WAN architectures

This chapter covers

  • Connecting remote sites using wide area network technologies
  • Different types of internet connections
  • Creating virtual private networks over the public internet

In the previous chapter, we covered local area networks (LANs) of various types and scales, from SOHO networks, to two- and three-tier campus LANs and even specialized data center networks that are essential for hosting an enterprise’s key servers. But LANs are just one piece of the puzzle; most enterprise networks are not confined to a single physical location.

Take, for example, a multinational corporation that has its headquarters in New York, manufacturing facilities in China, and regional offices scattered across Europe. Each of these locations will have its own local network, tailored for its specific needs. But these dispersed networks need to function as a unified whole, communicating and sharing resources securely and efficiently. Similarly, consider a retail chain with hundreds of stores, each with its own point-of-sale system, security cameras, guest Wi-Fi, and other network-connected devices. These stores also need to be integrated into a centralized system for inventory management, security monitoring, and data analytics.

16.1 WAN concepts

16.1.1 Leased lines

16.1.2 Multiprotocol Label Switching

16.2 Internet connections

16.2.1 Digital subscriber line

16.2.2 Cable internet

16.2.3 Fiber-optic Ethernet

16.2.4 Wireless 3G/4G/5G

16.2.5 Redundant internet connections

16.3 Internet VPNs

16.3.1 Site-to-site VPNs (Internet Protocol Security)

16.3.2 Remote access VPNs (Transport Layer Security)